American Memory (Library of Congress) http://memory.loc.gov/ammem/index.html
Internet Archive http://www.archive.org/
Making of America http://quod.lib.umich.edu/m/moagrp/ 19th century books and magazines
19th Century American Literary, Historical and Cultural Studies Online Resources http://public.wsu.edu/~amerstu/19th/19th.html
Census records http://www.census.gov/population/www/censusdata/hiscendata.html
Colorado's Historical Newspapers http://www.coloradohistoricnewspapers.org/Default/Skins/Colorado/Client.asp?Skin=Colorado&AW=1329762697358&AppName=2
Search engines can be helpful when you are researching a narrow topic or trying to locate a specific document. When searching, use specific terms rather than broad terms. For example search for the “emancipation proclamation” not just “slavery,” search for the “battle of chancellorsville” not “civil war.”